A Stellar Stream around the Spiral Galaxy Messier 61 in Rubin First Look Imaging

We present the first stellar stream discovered with the Vera C. Rubin Observatory, around spiral galaxy M61 (NGC 4303) in Virgo First Look imaging. The stream is narrow, radially-oriented in projection, and ∼ 50 kpc long. It has g-band surface brightness μg ∼ 28 AB mag arcsec−2, color g − z ∼ 1.0, and stellar mass M⋆ ∼ 2 × 108M⊙. This dwarf galaxy interaction may have provoked the M61 starburst, and foreshadows the bounty of accretion features expected in the ten-year Rubin Legacy Survey of Space and Time.